JP3562236B2 - Compressed air screw tightening machine - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressed air screwdriver for screwing a screw into a member to be tightened, and to reduce the size of an air motor so as to reduce the size of the entire screwdriver.
[0002]
[Prior art]
A number of screw tightening machines have been proposed in which a driver bit rotated by an air motor is lowered by a piston and screwed down. As a typical example, both the air motor and the driver bit are lowered as disclosed in Japanese Patent Application Laid-Open No. 45579/1994. Alternatively, there is an air motor in which the driver bit is lowered without lowering the air motor as disclosed in Japanese Patent Application Laid-Open No. 5-261676.
[0003]
In the former case, the weight of the moving section including the air motor occupies most of the weight of the screw tightening machine, and the weight of the moving section increases. As a result, the recoil at the time of screw tightening increases.
In the latter, an air motor is fixed in order to reduce the recoil at the time of screw tightening, and only a light moving member in which a driver bit and a piston are integrated is lowered and screwed.
[0004]
[Problems to be solved by the invention]
The latter screw tightening machine made it possible to reduce the recoil during screw tightening, but because the air motor rotor also functions as a cylinder, the air motor rotor becomes larger by the diameter of the cylinder. It becomes larger in the radial direction, and a new problem has arisen in that the size of the entire screw tightening machine is not expected to be reduced and the weight cannot be reduced.
SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned disadvantages of the prior art and to reduce the size of an air motor, and as a result, to reduce the size of the entire screw tightening machine.
[0005]
[Means for Solving the Problems]
The above object is achieved by extending a bottomed cylindrical rotating body, which is rotated by an air motor and provided with a rotation transmitting portion on an inner wall, and locks an upper end with a rotating slide member provided vertically and rotatably in the rotating body. This is achieved by a configuration in which the shaft member having the driver bit mounting portion and the piston portion at the lower end portion is rotated while being lowered.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to FIGS. 1-2.
Inside the body 1 forming the outer frame of the main body, there is a pressure accumulating chamber 4 communicating with a compressed air intake 27, and an air motor 2 having a rotor 3 rotatably supported upward. A bottomed cylindrical rotating body 9 rotated via 6 is rotatably supported. A ventilation hole 51 is provided in a substantially central side wall of the rotating body 9 in the axial direction. In the groove 23 of the body 1 facing the ventilation hole 51, a cylindrical main valve 5 which can be moved up and down is provided by being urged upward by a spring 22. A ventilation hole 52 communicating with the operation valve 24 is provided below the groove 23. The upper and lower sides of the main valve 5 are sealed, and a vent hole 53 is provided in the center. Above the groove 23, a ventilation hole 54 communicating with the pressure accumulating chamber 4 is provided. At least a pair of concave portions 10 extending in the axial direction are provided on the inner wall of the rotating body 9. The rotary slide member 7 having a pair of convex portions 8 inserted above the concave portions 10 is provided with an air blocking surface 11 described later and an O-ring 12 having a diameter to be inserted and sealed in a cylinder 15 described later. A driver bit mounting portion is provided inside a lower portion of the shaft member 28 whose upper end is locked to the rotating slide member 7 by means of, for example, screws, and a piston portion 13 having a seal ring mounted on the outer periphery of the lower end portion. Is provided. The driver bit 16 is mounted on the driver bit mounting portions of the rotary slide member 7 and the shaft member 38. Above the cylinder 15, a damper plate 14 is provided which comes into contact with the air blocking surface 11 when the rotary slide member 7 has descended a predetermined distance, and a vent hole 56 is provided below the damper plate 14. The ventilation hole 56 communicates with an air inlet (not shown) of the air motor 2 via an air passage (not shown). A piston damper 17 is provided at a lower end of the cylinder 15, and a vent hole 57 and a vent hole 58 are provided below the cylinder 15. The O-ring 21 constituting the one-way valve is provided on the outer periphery of the ventilation hole 57. Between the lower part of the body 1 and the outer periphery of the cylinder 15, a return accumulator chamber 20 of a well-known configuration in an air nailing machine is formed. Below the body 1, there is provided a screw feed portion 19 for automatically feeding the connection screw 18 connected by a connection band (not shown) in the magazine 25. Below the feed screw portion 19 push lever 26 is provided with the communication contact with the operating valve 24.
[0007]
The operation of the compressed air screw tightening machine of the present invention configured as described above will be described below.
When the compressed air inlet 27 is connected to a compressor (not shown), compressed air flows into the lower groove 23 of the main valve 5 through the pressure accumulating chamber 4, the operation valve 24, and the vent hole 52, and the main valve is operated by the air pressure and the spring 22. 5 is pushed upward to seal the upper end surface of the main valve 5. That is, the space between the pressure accumulating chamber 4 and the ventilation hole 51 of the rotating body 9 is shut off so that compressed air is not supplied to the piston 13 and the air motor 2.
[0008]
Actuating the push lever operated valve 2 4, the compressed air beneath the main valve 5 is discharged through the vent hole 52, the operation valve 24. Since compressed air pressure is applied near the outer periphery of the upper surface of the main valve 5, the main valve 5 is pushed down against the spring 22. For this reason, compressed air flows into the rotating body 9 through the ventilation hole 54 and the ventilation hole 51 of the rotating body 9 and the like, and air pressure is applied to the upper surface of the piston portion 13 to push the piston portion 13 downward, and at the same time, the ventilation hole 56 The compressed air is also supplied to the air motor 2 communicated with the air motor 2 to rotate the rotor 3 of the air motor 2. The rotation of the rotor 3 rotates the rotating body 9 and the rotating slide member 7 inserted into the rotating body 9 via the planetary gear device 6. As a result, the piston portion 13 and the driver bit 16 at the lower end of the shaft member 28 locked by the rotary slide member 7 rotate simultaneously while descending. When the driver bit 16 is lowered and rotated, the connecting screw 18 below the driver bit 16 is detached from the connecting band and screwed into the workpiece 80.
[0009]
As shown in FIG. 2, when the driver bit 16 is lowered to the screwing completion position, the piston 13 abuts against the piston damper 17, and the air blocking surface 11 of the rotary slide member 7 abuts against the damper plate 14, and stops lowering. At this time, the O-ring 12 of the rotary slide member 7 seals the upper end side of the inner circumference of the cylinder 15, and the abutment of the air blocking surface 11 closes the ventilation hole 56, stopping the supply of the compressed air to the air motor 2. . Therefore, the rotation of the rotor 3 of the air motor 2 is stopped, and the rotations of the planetary gear unit 6, the rotating body 9, the rotating slide member 7, the piston 13, and the driver bit 16 are stopped. In this state, compressed air flows from the pressure accumulating chamber 4 into the return pressure accumulating chamber 20 through the ventilation holes 54, the ventilation holes 51, the upper chamber of the rotary slide member 7, the ventilation holes 55, and the ventilation holes 57. Compressed air also flows into the lower surface side of the piston portion 13 through the same. Since the pressure receiving area of the piston portion 13 is large on the upper surface side, the piston portion 13 is stopped by being pressed against the piston damper 17.
[0010]
When the operation valve 24 is returned, the compressed air flows from the pressure accumulating chamber 4 into the groove 23 below the main valve 5 through the operation valve 24 and the ventilation hole 52, and pushes the main valve 5 upward. Therefore, as described above, the space between the pressure accumulating chamber 4 and the ventilation hole 51 of the rotating body 9 is shut off, and at the same time, the ventilation hole 53 at the center of the main valve 5 communicates with the exhaust passage 59 through an air passage (not shown), thereby The compressed air on the upper surface of the portion 13 is discharged outside the body 1. The compressed air in the return pressure accumulating chamber 20 is prevented from being discharged through the vent hole 57 by the O-ring 21. As a result, the piston 13 and the driver bit 16 are returned to the upper initial position by the air pressure acting on the lower surface of the piston 13. At the same time, the next screw 18 is fed onto the axis of the driver bit 16 by the screw feed unit 19 and returns to the initial state.
[0011]
According to the above-described embodiment , the rotation transmitting portion between the rotating body 9 and the rotary slide member 7 is configured to have a concave-convex engagement, and the distance between the rotation transmitting portion and the rotation center is determined by the rotation transmitting portion disclosed in Japanese Patent Application Laid-Open No. 5-261676. Since the distance between the rotation center and the spline between the moving member and the rotor of the air motor can be made much smaller, the force acting on the rotation transmitting unit can be reduced, and the surface pressure acting on the rotation transmitting unit can be reduced. Become smaller. As a result, the rotating body 9 and the rotating slide member 7 can be manufactured from an inexpensive material such as plastic, and the manufacturing can be made inexpensively and easily because only the irregularities need to be formed.
[0012]
In addition, since the planetary gear device 6 is provided to reduce the rotation of the air motor 2 and transmit it to the rotating body 9, a small-torque, high-speed rotation air motor can be used, and the air motor 2 can be downsized and, consequently, the entire screw tightening machine. Can be downsized and operability can be improved. Further, since the planetary gear device 6 is used as the speed reducing means, the air motor 2, the rotating body 9, the piston portion 13, the driver bit 16 and the like can be arranged coaxially, and the balance of the entire screw tightening machine is improved, and the operability is improved. Can be further improved.
[0013]
In the above-described embodiment , the piston portion 13 is provided integrally with the lower end of the shaft member 28. However, the lower end portion of the member attached to the shaft member 28 is used as a piston portion, and the piston portion 13 is formed as a separate member from the shaft member 28. Is also possible, and various modifications are possible.
[0014]
【The invention's effect】
As described above, according to the present invention, since the air motor, the rotating body, and the rotating slide member are separated, the diameter of the air motor can be reduced, that is, downsized, and the body can be downsized. As a result, the entire screw tightening machine can be downsized. Operability can be improved.
In addition, since the rotation transmitting portion of the rotating body and the rotary slide member is formed as a concave portion and a convex portion, it can be manufactured at a low cost, and the surface pressure acting on the rotation transmitting portion can be reduced. It can be manufactured with inexpensive materials.
[0015]
Since the deceleration means for decelerating the rotation of the air motor is provided, the size of the air motor can be further reduced, and the screw tightening machine as a whole can be reduced in size, thereby improving operability.
Furthermore, since the reduction gear is a planetary gear device, the air motor, the rotating body, the piston, and the driver bit can be arranged coaxially, and the overall balance when holding the handle in a magazine with screws stored in actual work can be improved. Various operational effects such as good operability can be obtained.
[Brief description of the drawings]
Cross-sectional side view showing an embodiment of the present invention; FIG.
FIG. 2 is a sectional side view showing the operation state of FIG. 1;
[Explanation of symbols]
1 is a body, 2 is an air motor, 6 is a planetary gear set, 7 is a rotary slide member, 8 is a convex portion, 9 is a rotating body, 10 is a concave portion, 11 is an air blocking surface, 12 is an O-ring, 13 is a piston portion, Reference numeral 15 denotes a cylinder, 16 denotes a driver bit, 18 denotes a screw, 19 denotes a screw feed portion, and 28 denotes a shaft member.

Claims (2)

A compressed air screw tightening machine for rotating a driver bit and moving a driver bit by compressed air through an air motor to tighten a screw to a member to be tightened,
And air motor provided above, is driven by an air motor, at least formed of a pair of recesses, the rotation transmission portion is a cylindrical rotating body provided in the inner wall having a diameter larger than that of the driver bit, a screw to the rotational body moving and rotating in the clamping direction is provided as possible, and the rotary slide member rotates the transmission section formed from at least a pair of projecting portions to be engaged with the rotation transmission portion of the rotating body is provided on the outer wall, an upper end Is fixed to the rotating slide member, a driver member is provided at the lower end, and a shaft member formed with a piston portion and a piston portion. The shaft member is provided below the rotating body, and the piston portion is moved in the screw tightening direction. and a Cylinders that can as support, rotator, rotating the slide member, via the piston unit rotates the driver bit via a shaft member de Ibabitto allowed to move to the screwing direction, compressed air screw driver, characterized in that it has to tighten the screw by striking and rotating the screw by a driver bit. 2. The compressed air screw tightening machine according to claim 1, wherein a speed reducing means for reducing the rotation of the air motor and transmitting the rotation to the rotating body is provided between the air motor and the rotating body .

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